1. Field of the Invention
The present invention relates to a method for detecting a physiological signal, in which at least one ventilation parameter is measured and analyzed to control a ventilation pressure.
The invention also concerns a device for detecting a physiological signal, which has a sensor for measuring a ventilation parameter and a control unit for producing a ventilation pressure.
The invention further concerns a device for monitoring at least one ventilation parameter while respiratory gas is being supplied to a patient, which has a sensing device for detecting the behavior of the ventilation parameter as a function of time.
2. Description of the Related Art
Large numbers of persons suffer from sleep disorders, which affect the well-being of these persons during the day and in some cases have an adverse effect on their quality of life. One of these sleep disorders is sleep apnea, which is treated primarily by CPAP therapy (CPAP=continuous positive airway pressure), in which a flow of respiratory gas is continuously supplied to the patient through a nasal mask as the patient sleeps. A hose connects the mask with a ventilator, which includes a blower that produces a gas flow with, for example, a positive pressure of 5 to 20 mbars.
The gas flow is supplied to the patient either at constant pressure or, to relieve the respiratory work of the patient, at a lower level during expiration.
The lowering and raising of the ventilation pressure are effected on the basis of various events identified by the device and by measured respiratory parameters.
The following are examples of such events: mouth expiration, mouth breathing, leakage, swallowing, speaking, sneezing, coughing, increase in respiratory flow, decrease in respiratory flow, flattening of the respiratory flow, cessation of respiratory flow, increase in resistance, leakage, apnea, hypopnea, snoring, inspiration, expiration, interruption of breathing, increase in respiratory volume, decrease in respiratory volume, inspiratory constriction of the respiratory flow, inspiratory peak flow, decrease in the inspiratory flow after peak flow, second maximum of the inspiratory peak flow, increase in the pressure of the respiratory gas, decrease in the pressure of the respiratory gas, increase in the flow of the respiratory gas, decrease in the flow of the respiratory gas, increase in the volume of respiratory gas delivered, decrease in the volume of respiratory gas delivered.